1. Field
Embodiments of the invention relate to the field of compression ignition engines; and more specifically, to the field of compression ignition engines capable of using either liquid or gaseous fuel.
2. Background
U.S. Pat. No. 7,793,638 discloses low emission high performance engines, multiple cylinder engines and operating methods that introduce numerous methods of operating unique engine configurations, the disclosure of which is hereby incorporated by reference. Among the engine configurations disclosed is a camless configuration having conventional intake and exhaust valves, and valves and manifolds coupled to low pressure and high pressure rails in a multi cylinder engine. In such an engine, some cylinders were devoted to operation as compression cylinders for supplying air at the appropriate pressure to the low pressure air rail and to the high pressure air rail and some cylinders are used as combustion cylinders having an injector, intake and exhaust valves and low pressure and high pressure air rail valves to allow the injection of air and fuel into the combustion cylinder at various stages of the operation of the combustion cylinder. The fuel used may be either a gaseous fuel or a liquid fuel (not both in the same engine), as the operation of the camless engine with electronic control of the valves and injectors allows control of both compression ignition and combustion for maximum power with minimum emissions.